Abstract: A glass fiber-reinforced composite material is produced by treating glass fibers with a silane composition comprising silane molecules having amine functional groups and silane molecules having ethylenically-unsaturated functional groups; admixing the treated glass fibers with a polyolefin resin, and a fiber bonding agent comprising a polymerizable unsaturated organic compound having at least two polymerizable unsaturation groups, a vinyl-polymerizable unsaturated, hydrolyzable silane, and a free radical generator, and exposing the resultant mixture to conditions of temperature and pressure sufficient to cause the formation of a glass fiber-reinforced composite material. The use of the silane composition promotes improved impact strength of the composite.